if it's processed correctly (to get rid of bacteria, diseases, etc.) then it's fine for your fish. I never tell people which kind of food is best, because it's best to feed your fish (and yourself!) a wide variety of foods. If you stick with one type (be it flakes, pellets, whatever) they're going to get deficiencies because no one kind of food contains all the nutrients they need.
yes, some people even feed their fish fresh vegetables like peas, dark lettuce, broccoli, zucchini, spinach, etc. even oranges! I personally feed veggies, flakes, pellets, bottom feeder wafers, frozen food (glassworms, bloodworms, brine shrimp, mysis), freeze-dried Daphnia and sometimes live food. They love the variety and it's better for them.
sorry if that was overwhelming. just start out slowly, give them something new. experiment and see what they'll eat. after awhile it gets fun, like playing chef for you fishies
